There simply is no information yet about what Hasan’s motives were, or whether Hasan is indeed muslim or not. Of course, that last bit of information is the one that everyone will want to know about the most, even though in a fundamental sense it matters the least. (…)
However, something disquieting about the date… It should be noted (as others like Ali Eteraz already have) that today is Guy Fawkes Day – the anniversary of a plot by a Catholic dissident to blow up the English Parliament then dominated by Protestants).
If the shootings were motivated by some sense of grievance against US foreign/military policy, then the date is surely significant.